Search result previews

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing search result page previews. In one aspect, a method includes receiving data that specify a set of search results responsive to a search query. Query-relevant content is selected to be included in a page preview for at least one of the search results. In turn, data that cause presentation of the page preview are provided. The data provided can cause presentation of the query-relevant content at an initial zoom level and at a higher zoom level, where the initial zoom level is a zoom level at which both the query-relevant content and other content from the resource are presented. The page preview can include a page tear that defines multiple portions of the page preview for a resource.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Patent Application No. 61/380,613, entitled “SEARCH RESULT PREVIEWS,”filed Sep. 7, 2010, which is incorporated herein by reference in itsentirety.

BACKGROUND

This specification relates to digital information retrieval andpresentation.

The Internet provides access to a wide variety of resources such asvideo or audio files, web pages for particular subjects, book articles,or news articles. A search system can identify resources in response toa text search query that includes one or more search phrases (i.e., oneor more words). The search system ranks the resources based on measuresof relevance of the resources to the search query and on measures ofquality of the resources. In turn, the search system selects a quantityof the ranked resources and provides search results that link to theselected resources. The search results are typically ordered for viewingaccording to the rank of the resource to which the search result links,and provided in a search results page.

The search results page displays a list of search results, and eachsearch result includes several lines of text (a “snippet”) that areintended to show how the resource to which the search result links isrelevant to the query. However, this snippet of text may not provide theuser with enough information for the user to determine whether theresource referenced by the search result provides data that the userprefers. Thus, the user may need to click on multiple search results andscroll through or search the web pages (or other resources) that arelinked to by the search results in order to find data that is formattedin the manner that the user prefers.

SUMMARY

In general, one innovative aspect of the subject matter described inthis specification can be embodied in methods that include the actionsof receiving data that specify a set of search results responsive to asearch query, the search query including one or more query terms;selecting, for at least one search result in the set of search results,a set of query-relevant content to be included in a page preview for thesearch result, the page preview being a visual representation of aresource that is referenced by the search result; inserting a page tearinto the page preview, the page tear defining a first portion and asecond portion of the page preview, the first portion being differentfrom the second portion; inserting first query-relevant content from theresource into the first portion of the page preview; inserting secondquery-relevant content form the resource into the second portion of thepage preview, the second query-relevant content being content selectedfrom a portion of the resource that is not presented in the firstportion of the page preview; and providing data that cause presentationof the page preview. Other embodiments of this aspect includecorresponding systems, apparatus, and computer programs, configured toperform the actions of the methods, encoded on computer storage devices.

These and other embodiments can each optionally include one or more ofthe following features. Methods can further include the actions ofidentifying, as query-relevant content, text in the resource thatmatches at least one query term of the search query; and analyzing acontext of the query-relevant content, the context including a locationof the query-relevant content and other content that appears within athreshold distance from the query-relevant content. Selecting a set ofquery-relevant content can include selecting, based on the context, thequery-relevant content that satisfies a minimum relevance threshold.

Analyzing the context can include determining a quantity of query termsthat are within a threshold number of pixels of the query-relevantcontent; determining a total quantity of query terms that are includedin the resource; computing a first score for the query-relevant contentbased on the quantity of query terms and the total quantity of queryterms; determining a content category for the query-relevant content;and adjusting the first score based on the content category for thequery-relevant content.

Adjusting the first score can include reducing the first score inresponse to determining that the content category is one of a footnoteor anchor text that links to another resource. Providing data that causepresentation of the page preview can include providing data that causepresentation of the first portion of the page preview and the secondportion of the page preview at presentation positions that representrelative locations of the first query-relevant content and the secondquery-relevant content in the resource.

Providing data that cause presentation of the page preview can includeproviding data that causes presentation of the page preview at a pagepreview slot that is adjacent to the search query. Providing data thatcause presentation of the page preview can include providing data thatcause presentation of the page preview in response to user selection ofa page preview user interface element that is presented with the searchresults.

Providing data that cause presentation of the page preview can includeproviding data that includes a link to the resource referenced by thesearch result. Providing data that includes a link to the resource caninclude providing data that includes a first link to a location of theresource at which the first query-relevant content is located andfurther includes a second link to a location of the resource at whichthe second query-relevant content is located. The first link can beassociated with the first portion of the page preview and the secondlink is associated with the second portion of the page preview.

Providing data that cause presentation of the page preview can includeproviding data that cause presentation of the page preview in responseto user selection of any portion of the search result other than a linkto the resource referenced by the search result. Providing data thatcause presentation of the page preview further can include providingdata that cause the search result to be highlighted in response toreceiving data indicating that a pointing device indicator is locatedover the search result. Providing data that cause presentation of thepage preview can include providing data that cause the firstquery-relevant content to be presented with a larger font than at leasta portion of other content included in the first portion of the pagepreview.

Another innovative aspect of the subject matter described in thisspecification can be embodied in methods that include the actions ofreceiving data that specify a set of search results responsive to asearch query, the search query including one or more query terms;selecting, for at least one search result in the set of search results,a set of query-relevant content to be included in a page preview for thesearch result, the page preview being a visual representation of aresource that is referenced by the search result; and providing datathat cause presentation of the page preview, the data comprising datathat cause presentation of the query-relevant content at an initial zoomlevel and at a higher zoom level, the initial zoom level being a zoomlevel at which both the query-relevant content and other content fromthe resource are presented in the page preview, the higher zoom levelbeing a zoom level that is higher than the initial zoom level. Otherembodiments of this aspect include corresponding systems, apparatus, andcomputer programs, configured to perform the actions of the methods,encoded on computer storage devices.

These and other embodiments can each optionally include one or more ofthe following features. Selecting a set of query-relevant content caninclude selecting query-relevant text that matches the search query.Providing data that cause presentation of the page preview can includeproviding data that cause presentation of an instance of thequery-relevant text at the initial zoom level; and providing data thatcause presentation of another instance of the query-relevant text at thehigher zoom level. The query-relevant text can be presented at thehigher zoom level and visibly emphasized relative to other contentpresented in the page preview.

Selecting a set of query-relevant content can include selecting at leastone query-relevant image. Providing data that cause presentation of thepage preview can include providing data that cause presentation of aninstance of the query-relevant image at the initial zoom level; andproviding data that cause presentation of another instance of thequery-relevant image at the higher zoom level. Providing data that causepresentation of the page preview can further include providing data thatcause a portion of the page preview that is presented at both theinitial zoom level and the higher zoom level to be visibly emphasized atthe initial zoom level.

Methods can further include the actions of determining that the resourceincludes additional query-relevant content that is not presented in thepage preview; and providing data that cause presentation of theadditional query-relevant content with the page preview, thepresentation of the additional query-relevant content including a userinterface element indicating that the additional query-relevant contentis located at a portion of the resource that is not presented in theinitial page preview.

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. Page preview snippets reduce the quantity of pagesthat users visit prior to obtaining information for which the users aresearching, thereby reducing the time required for the users to findinformation that satisfies their informational needs, and creating amore streamlined user search experience. Users are able to determinewhich resources provide data in preferred formats and/or contexts usingpage previews that are presented with search results.

Page tears enable content from different portions of a resource to bepresented in a single page preview slot that is adjacent to searchresults, showing more relevant page sections than could fit in acontiguous page preview. Accordingly, the users need not navigate fromthe search results pages to the resources to determine which resourcessatisfy their informational needs and which do not.

The details of one or more embodiments of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example environment in which a searchsystem provides search services.

FIG. 2 is a block diagram of a web page that is being represented in apage preview slot.

FIG. 3 is a screen shot of an example search results page in which apage preview is presented.

FIG. 4 is a block diagram of a page preview generated using content froma web page.

FIG. 5 is a block diagram of an example page preview to which a zoomfeature is applied.

FIG. 6 is an example process for generating page previews.

FIG. 7 is another example process for generating page previews.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a search environment 100 that facilitatesresource search operations on a client device. The example environment100 includes a network 102, e.g., a local area network (LAN), wide areanetwork (WAN), the Internet, or a combination of them. The network 102connects Websites 104, client devices 106, and the search system 110.The environment 100 may include many thousands of publishers 104 andclient devices 106.

A Website 104 is one or more resources 105 associated with a domain nameand hosted by one or more servers. An example Website is a collection ofWeb pages formatted in hypertext markup language (HTML) that can containtext, images, multimedia content, and programming elements, e.g.,scripts. Each Website 104 is maintained by a publisher, e.g., an entitythat manages and/or owns the Website.

A resource 105 is any data that can be provided by a Website 104 overthe network 102 and that is associated with a resource address.Resources 105 include HTML pages, word processing documents, andportable document format (PDF) documents, images, video, and feedsources, to name just a few. The resources 105 can include content,e.g., words, phrases, images and sounds and may include embeddedinformation (e.g., meta information and hyperlinks) and/or embeddedinstructions (e.g., JavaScript scripts).

A client device 106 is an electronic device that is under control of auser and is capable of requesting and receiving resources 105 over thenetwork 102. Example client devices 106 include personal computers,mobile communication devices, and other devices that can send andreceive data over the network 102. A client device 106 typicallyincludes a user application, e.g., a web browser, to facilitate thesending and receiving of data over the network 102.

To facilitate searching of resources 105, the search system 110identifies the resources 105 by crawling and indexing the resources 105provided on Websites 104. Data about the resources 105 can be indexedbased on the resource to which the data corresponds. The indexed and,optionally, cached copies of the resources 105 are stored in searchindex 112.

The client devices 106 submit search queries 109 to the search system110. For instance, any particular search query 109 can include one ormore terms consisting of words, numbers or other characters. As anexample, the search query 109 entered by the user can be “puzzle cube”to search online for information regarding geometric cube puzzles. Inresponse to receipt of the search query 109, the search system 110accesses (e.g., using a search engine) the search index 112 to identifyresources 105 that are relevant to the search query 109. The searchsystem 110 identifies the resources 105, generates search results 111that identify the resources 105, and returns the search results 111 tothe client devices 106.

For example, the search results 111 can include resources 105 that havebeen identified as having at least a threshold relevance score for thesearch query “puzzle cube.” A search result 111 is data generated by thesearch system 110 that identifies a resource 105 that is responsive to aparticular search query, and includes a link to the resource 105. Anexample search result 111 can include a Web page title, a snippet oftext or a portion of an image extracted from the Web page, and the URLof the Web page.

For a search of textual content, the search results are ranked based onrelevance scores of the resources 105 identified by the search results111. The relevance scores can be computed, for example, based oninformation retrieval (“IR”) scores, and optionally a quality score ofeach resource relative to other resources. In some implementations, theIR scores are computed from dot products of feature vectorscorresponding to a search query 109 and a resource 105. Quality scorescan be computed, for example, based on visual characteristics of thepage, such as page layout, font sizes, and a quantity of imagespresented on the page. The quality scores can also be computed based onuser feedback regarding page quality and/or a determination of whetherthe page includes, or links to a page that includes, malware (e.g.,computer viruses). The search results 111 are ordered according to theserelevance scores and provided to the client device 106 for presentationaccording to the order.

The client devices 106 receive the search results 111, e.g., in the formof one or more search result pages 126, and render the search results111 for presentation to users. The search results 111 include dataspecifying a set of resources 105 that have been identified as relevantto the search query submitted by the client device 106 (e.g., based onrelevance scores). As noted above, the search results 111 can alsoinclude a “snippet” from the resource 105 that has been identified asrelevant to the search query 109. For example, a snippet can be twolines of text that represent the contents of the resource 105 that islinked to by the search result 111.

A snippet generally includes one or more “tidbits” that have beenidentified in the textual content of the resource 105 that is linked toby the search result 111. As used herein, a “tidbit” is text that can beincluded in a snippet. In some implementations, a tidbit is a portion ofcontiguous text in the resource, such as a group of adjacent words inthe search result 111 displayed on the user's client device 106. Eachsearch result 111 can include one or more snippets, where each snippetincludes one or more tidbits. Tidbits can be identified, for example, bythe search system 110 and/or a preview apparatus 120 (described below).

A search result 111 that includes a snippet provides a user with datathat enables the user to determine whether to request presentation ofthe resource 105 that is linked to by the search result 111. Forexample, using data provided by the snippet, the user can determinewhether a web page includes content for which the user is searching.However, a snippet may not provide the user with data specifying thecontext (e.g., content location, and/or nearby content) in which contentrelevant to their search query is presented, the format of thepresentation, or data specifying web page display characteristics (i.e.,page length, images that are included in the page, page formattinginformation) for the web page, or, if the snippet does provide someindication of the context or format, it may not provide enoughinformation for the user to determine whether the resource would satisfythe user's informational needs. Therefore, the user may be required tovisit the web page in order to make the determination.

Some users that are searching for data begin their search with aninitial preference of the format (“format preference”) in which theywould like to receive the content for which they are searching. Forexample, a particular user that is searching for “puzzle cube” mayprefer to view pages that provide text instructions (e.g., in a numberedor bulleted list) to solve a particular puzzle cubes, while another userthat submits that same search query may want to receive a series ofphotos that illustrate how to solve the particular puzzle cube. Inanother example a user that enters the search query “sports scores” maywant sports scores provided in a table format (e.g., box scores), whileanother user may be interested in receiving sports scores withinarticles that recap the sporting event. Since different users may havedifferent preferences of how they want information presented, andbecause these preferences may change from one search to another, it canbe difficult to determine which display characteristics each usersprefers for each search query.

In some implementations, the search system 110 provides users with dataabout the format in which data is presented by a web page. A clientdevice 106, using data provided by the search system 110, displayscharacteristics of the web page to provide “page previews” with thesearch results. Page previews are visual representations (e.g., images)of a web page to which a search result links. In some implementations,images of web pages are stored in a data store that is accessible by thesearch system 110. The images that are stored can represent a thresholdnumber of page pixels (e.g., 10,000 pixels) for each page. Theresolution of the image can be reduced by a reduction factor (e.g., ⅓)to reduce the amount of data stored for each web page. When a pagepreview is selected to be presented to a user, a portion of the pagepreview (e.g., ⅓ of the reduced resolution representation) can beselected to be presented to the user, as described below.

FIG. 1 includes two example page previews 130 a and 130 b, each of whichis rendered in page preview slots 134. Page preview 130 a presents aportion of web page 131 a to which search result 111 a links, while pagepreview 130 b presents a portion of web page 131 b to which searchresult 111 b links. The portion of the web page presented in the pagepreview 130 a only includes text, while the portion of web page that ispresented in the page preview 130 b includes text and images 132. Usingthe page previews 130 a and 130 b, a user can obtain information aboutthe formatting of the web pages to determine which of the web pages isformatted in a manner that the user prefers for this particular search.However, content not included in the page previews 130 a, 130 b mayprovide additional information about the formatting of the web page, asdescribed in more detail with reference to FIG. 2.

Portions of a search result page in which page previews are presentedare referred to as page preview slots 134. The size of a page previewslot may be fixed or decided according to the available whitespace, ormay be proportional to a size of the search result 111 with which thepage preview is associated (i.e., the search result that links to thepage represented by the page preview). For example, a page preview slotfor a particular search result can be required to occupy a same quantity(or fewer) vertical pixels as the particular search result.Additionally, the quantity of horizontal pixels occupied by the pagepreview slot can be limited based on the white space that exists betweenthe particular search result and a visible edge of the page that ispresented by the client device 106. In some implementations, the size ofeach page preview slot is selected to be proportional to an aspect ratioof a web page for which a page preview is being generated, or evenproportional to the size of the resource the preview represents.

Size limitations for page previews 130 may prevent the user from beingable to determine whether the formatting of the web page represented bythe page preview 130 satisfies the user's format preference, or whetherthe content of the web page represented by the page preview 130 isrelevant to the user's search query. This is described with reference toFIG. 2, which is a block diagram of a web page 200 that is beingrepresented in a page preview slot 134. As illustrated by FIG. 2, thesize of the page preview slot 134 is smaller than the size of the webpage 200. When the size of the page preview slot 134 is smaller thanand/or has a different aspect ratio than the web page 200 that is beingrepresented in the page preview slot 134, portions of the web page 200will not be presented in the page preview slot 202.

If the portions of the web page 200 that are not presented in the pagepreview slot 134 are relevant to the user's search query and/or provideadditional information about the content, context, and/or format of theweb page 200, the user is unable to use this additional information todetermine whether to request presentation of the web page 200. Forexample, if the portion of the web page 200 that is outlined by the pagepreview slot 134 is the only portion of the web page 200 that ispresented to the user in the page preview slot, the user may be unawarethat the web page 200 includes a table 208 and images 210. Thus, basedon the portion of the web page 200 that is presented in the page previewslot 134, the user may not click the search result that links to the webpage 200 if the user is looking for web pages that include imagesrelevant to the user's search query. Additionally, the user is alsounable to determine the length of the web page based on the pagepreview.

In some implementations, the size of the web page 204 can be reduced sothat a larger portion of the web page 200 can be presented in the pagepreview slot 202. For example, if the resolution of the representationof the web page 200 (e.g., an image of the web page) is reduced (i.e.,relative to an initial resolution), the portion of the web page 200 thatis outlined by the box 206 may be able to be presented in the pagepreview slot 134. However, reducing the resolution of the web pagerepresentation that is presented in the page preview slot 134 willreduce the user's ability to use the page preview to determine thecontent of the web page. For example, the user may be able to determinewhere text and/or images are presented on a web page by viewing a webpage representation that has reduced resolution (relative to a fullscale representation), but the user may not be able to read text that ispresented in the page preview, or to view image details due to thelowered resolution.

Referring again to FIG. 1, the search system 110 is in datacommunication with a preview apparatus 120 that generates page previewsthat include page preview snippets. Page preview snippets are snippetsthat are presented in a page preview and include query-relevantinformation (e.g., query-relevant text or images). In someimplementations, query-relevant text in the page preview snippets can behighlighted or otherwise emphasized (e.g., bolded, italicized, orpresented in a different font color) relative to non-snippet text. Thepage preview snippets and/or query-relevant text can also be enlarged,as described in more detail with reference to FIG. 5.

Page preview snippets can be used to provide additional details aboutthe web page to the user. For example, in response to the search query“Belgian Waffles,” the search system 110 may determine that an onlineencyclopedia article about Belgian waffles is relevant to the searchquery, and generate a search result that links to the article. Thepreview apparatus 120 generates and/or provide a page preview for thesearch result that references the article. For example, the page previewthat is generated for the Belgian waffle encyclopedia may include animage of a Belgian waffle and a snippet that includes the text “Belgianwaffles are prepared with a yeast leavened batter.”

In some implementations, the search system 110 inserts both the searchresult and the page preview into the search results page that is beingprovided to the client device 106 in response to the search query. Inthese implementations, the search result and the page preview are bothpresented when the search results page is rendered. In otherimplementations, the search system 110 inserts a link (or anotherreference) to the page preview into the search result, such that thepage preview is presented in response to a request to view the pagepreview (e.g., a user click of a page preview icon or hypertext link, ora mouse over), as described in more detail below.

FIG. 3 is a screen shot of an example search results page 300 in which apage preview 312 is presented. The search results page 300 presentssearch results 306 a and 306 b that were identified as responsive to thesearch query “Belgian Waffles,” that was submitted using a search textbox 304. Each of the search results 306 a, 306 b includes a snippet 310a, 310 b. The search result 306 a also includes a page preview 312 thatis presented in page preview slot 314. The page preview 312 includes asnippet 310 c that the search system 110 identified as relevant to thesearch query “Belgian Waffles,” as well as an image 316 that the searchsystem 110 identified as relevant to the search query (e.g., based on acaption for the image, a filename of the image, or text within aspecified number of pixels of the image).

In some implementations, the snippet 310 c (and each other snippetpresented in a page preview) can be a different snippet than the snippet310 a that was selected for inclusion in the search result 306 a. Forexample, the page preview slot 314 may provide more space in whichsnippets and/or other content can be presented. Therefore, the snippet310 c selected by the preview apparatus 120 can be a snippet that wasnot eligible to be included in the search result snippet 310 a based onsnippet size restrictions associated with the search result 306 a.

Additionally, the preview apparatus 120 can filter snippets that havebeen included in the search result 306 a may from a set of snippets thatare available for inclusion in the page preview 312. Alternatively, insome implementations, a threshold quantity of snippets that have notbeen included in the search result 306 a may be selected by the previewapparatus 120 for inclusion in the page preview 312 before snippets thatare included in the search result 306 a are selected. Preferring (e.g.,though filtering and/or order of selection) snippets that have not beenincluded in the search result 306 a increases the variety of snippetsthat are presented to the user. For some search results, the thresholdquantity of snippets may be greater than a quantity of snippets thathave not been included in the search results 306 a. Therefore, thepreview apparatus 120 can also select snippets that have been includedin the search results 306 a. For example, if the threshold quantity ofsnippets is equal to or greater than a total quantity of availablesnippets for a search result, then the preview apparatus can select allof the available snippets for inclusion in the page preview 312.

Multiple snippets 310 and/or images 316 can be available for inclusionin a page preview 312. However, one or more of these snippets 310 and/orimages 316 may appear at portions of a web page that would not typicallybe included in a page preview 312, as described above with reference toFIG. 2. For example, the snippets 310 and/or images 316 may appearoutside of a contiguous area of the web page (or a reduced resolutionversion of the web page) that is able to be presented in the pagepreview slot 314. Thus, in some implementations, the preview apparatus120 of FIG. 1 generates a “page tear” in a page preview to indicate thatthe page preview is presenting a non-contiguous representation of theweb page. A page tear is a graphical user interface element thatprovides an indication that a portion of a web page is not presented bya page preview. For example, the page tear 318 is a graphical separation(i.e., defined by two curves) that is presented between the portion 320a of the page preview 312 in which the image 316 is presented and theportion 320 b in which the snippet 310 c is presented. A page tear isnot required to be defined by multiple curves or lines. For example, asingle line or curve could be used to represent a page tear.

Page tears can be used to present snippets 310 and/or images 316 thatare identified as relevant to a search query irrespective of thelocation of the snippets 310 and/or images on the web page. For example,assume that the image of the Belgian waffle 316 appears at the top ofthe encyclopedia article, while the snippet “Belgian Waffles areprepared with a yeast leavened batter” 310 c appears at the bottom ofthe encyclopedia article. Further assume that the length of theencyclopedia article prevents the entire encyclopedia article from beingpresented in a contiguous page preview (i.e., a page preview that doesnot include a page tear), while maintaining the legibility of thesnippet 310 c. For example, the preview apparatus 120 can determine thenumber of search results to be shown to determine the size of the pagepreview area. Using this size, the preview apparatus determines theapproximate font size (or reduction percentage) that would result inshowing a contiguous page preview; if the font size (or reductionpercentage) are below a threshold value, then a page tear is generated.In this example, a portion of the web page that includes the image ofthe Belgian waffle 316 can be presented in the portion 320 a of the pagepreview 312, while the snippet 310 c can be presented in the portion 320b that is separated from the portion 320 a by the page tear 318.

The preview apparatus 120 of FIG. 1 can include multiple page tears in asingle page view. For example, when query-relevant content (i.e., textand/or images) has been identified in several different portions of aweb page, the preview apparatus 120 can create three or more portions320 in which the query-relevant content can be presented. Each differentportion of the web page that has been identified can be presented in adifferent portion 320 of the page preview 312, and each of the differentportions can be separated from the other portions 320 by a page tear318.

In some implementations, the portion of the web page that is rendered ineach portion 320 of the page preview can be a disjoint portion of theweb page relative to the other portions of the web page that arepresented in each of the other portions 320 of the page preview. Forexample, each of the portions 320 a, 320 b of the page preview 312 canonly include content that is not included in the other portion 320 b,320 a of the page preview 312. Rendering disjoint portions of the webpage in the portions 320 of the page preview 312 facilitatespresentation of a page preview that is representative of a largerportion of the web page than the portion of the web page that might berepresented by a page preview 312 in which content presented in theportions 320 overlaps. In some implementations, content of a web page(e.g., snippets and/or images) can be presented in a portion of a pagepreview that represents the relative positioning of the web pagecontent, as described in more detail with reference to FIG. 4.

In some implementations, the search system 110 includes page previewelement 330 with the search result 306 a. The page preview element 330is a user interface element (e.g., an icon) indicating that a pagepreview is available for the search result. For example, the searchresults page 302 can be initially presented without displaying the pagepreview 312. In this, example, the page preview 312 can be presented inresponse to receiving data indicating that the user selected the pagepreview element 330.

Presentation of the page preview 312 can also be caused in response toreceiving data indicating that the user interacted with a portion of asearch result, for example clicking a designated icon or link, or anyportion of the search result 306 a other than the link 332 to theresource referenced by the search results. Additionally, the pagepreview can be presented in response to determining that a pointerindicator (e.g., a mouse pointer) has been located over the searchresult for at least a minimum specified time, or that a pointer orfinger completed a specific gesture.

FIG. 4 is a block diagram 400 of a page preview 402 generated by thepreview apparatus 120 using content from a web page 404 and snippet andtidbit locations provided by the search engine 110. The content 408,410, and 412 from the web 404 are inserted into page preview portions406 a-406 c that respectively represent the relative locations of thecontent in the web page 404. For example, web page portion 408 appearsat the top of the web page 404, and therefore is inserted at a top pagepreview portion 406 a. Similarly, web page portion 410 appears at thebottom of the web page 404, and therefore is inserted at a bottomportion 406 c of the page preview 402. The web page portion 412 islocated between the web page portion 408 and the web page portion 410.Therefore, the web page portion 412 is inserted into the page preview402 at portion 406 b, which is between portions 406 a and 406 c. Thus,each portion of the web page 404 is presented at a portion of the pagepreview 402 that represents the relative position of the content in theweb page 404.

In some implementations, the size of the page preview, and the size ofeach page tear can be selected to have a same aspect ratio as the webpage (or the portion of the web page represented). Thus, the portion ofthe content that is displayed in each portion of a page preview can bedetermined based on the aspect ratio of the web page and the size of thepage preview in which the content will be presented. Additionally, theportion of content displayed in each portion of a page preview can beselected based on a pre-specified amount of text (e.g., two sentences)to be included in each portion of the page preview, or based on apre-specified number of pixels of the web page to be included in eachportion of the page preview.

FIG. 5 is a block diagram of an example page preview 502 to which a zoomfeature is applied. A zoom feature can be applied a page preview toenlarge a portion of the web page content that is presented in the pagepreview. The page preview 502 includes two page preview portions 504 a,504 b in which two portions of a web page are presented. The portion 504a is presented at with an initial zoom level, while an image 506 a ispresented at a higher level of zoom (i.e., made larger) relative to theinitial zoom level. The initial zoom level can be a zoom level at whichweb page formatting, context, and content types are visuallydiscernable, while text may or may not be legible. The higher level ofzoom can increase the size of text and images relative to the initialzoom level so that zoomed text is legible and/or details of images aremore easily viewed.

For example, the image 506 a is an image of a Belgian Waffle presentedat an initial zoom level and the image 506 b is the image of the BelgianWaffle presented at a higher level of zoom. Presentation of the image506 a in the page preview portion 504 a provides a representation of theportion of the web page in which the image 506 a is presented so that auser can visually examine web page formatting (or content context) anddetermine what type of content is presented on the web page near theimage 506 a. For example, visual analysis of the portion 504 a allows auser to determine that the image 506 a is the only image presented inthe portion of the web page represented in the portion 504 a, and thattext 508 a is presented adjacent to the image 506 a.

The image 506 b provides a zoomed-in view (i.e., a largerrepresentation) of the image 506 a. The zoomed-in view presents a largerversion of the image 506 a so that visual details of the image are moreeasily perceived. Thus, a user can more readily determine whether theimage 506 b provides a level of visual detail that is preferred by theuser.

The portion 504 b includes text (e.g., a snippet) that is presented in asame portion of a web page as query-relevant text 510 a. Thequery-relevant text 510 a is presented in the portion 504 b at aninitial zoom level so that a user can visually examine web pageformatting, content context, and content types presented on the web pagenear the query-relevant text 510 a, as described above. The text box 510b provides a zoomed-in view of the query-relevant text 510 a. In someimplementations, the zoomed-in view presents the query-relevant text 510a with at least a minimum specified font size. For example, the text box510 b may present the query-relevant text at 12 point font so that thequery-relevant text is legible. Presenting zoomed-in text in the textbox 510 b enables a user to analyze the content of the web page withoutbeing required to navigate to the web page. The zoomed-in text may alsobe reformatted for consistency or legibility or to highlight sectionsrelevant to the user query, and may be edited for brevity.

In some implementations, zoomed-in views of images and/or query-relevanttext can be presented at locations that prevent occlusion (eitherpartial or total) of the images and/or query-relevant text that ispresented at the initial zoom level. For example, the image 506 b ispresented at a location of the page preview 504 a that does not occludeany of the text 508 a or the image 506 a. However, the text box 510 b ispositioned so that the query-relevant text 510 a is only partiallyoccluded by the text box 510 b.

In some implementations, the zoom feature can be implemented by a clientside script or instructions that the preview apparatus 120 provides withthe preview data. The zoomed-in views can be presented in pop-up widows,or can alternatively be rendered within the search results page usingdynamic formatting processes (e.g., manipulation of document objectmodel (DOM) elements).

FIG. 6 is an example process 600 for generating page previews. Theprocess 600 is a process by which search result data (i.e., data thatspecify a set of search results responsive to a search query) arereceived. Query-relevant content is selected from a resource that isreferenced by a search result in the set of search results. A context ofthe query-relevant content is analyzed and a set of query-relevantcontent is selected for inclusion in a page preview for the searchresult. Using the set of query-relevant content, a determination is madewhether the page preview should include a page tear. If the page previewshould not include a page tear, the page preview is generated using theset of query-relevant content. If the page preview should include a pagetear, a page tear is inserted into the page preview and query-relevantcontent is inserted into each portion of the page preview. In turn, datathat cause presentation of the page preview are provided.

The process 600 can be implemented, for example, by the previewapparatus 120 and/or the search system of FIG. 1. In someimplementations, the preview apparatus 120 is a data processingapparatus that includes one or more processors that are configured toperform actions of the process 600. In other implementations, a computerreadable medium can include instructions that when executed by acomputer cause the computer to perform actions of the process 600.

Data that specify a set of search results responsive to a search queryare received (602). In some implementations, the search query includesone or more query terms and the search results each represent a resourcethat has been determined to have at least a minimum threshold relevanceto at least one of the query terms. The data can include tidbits andsnippets that have been selected for presentation in the search result,and other tidbits and snippets that have not been selected forpresentation in the search result. The data that specify a set of searchresults can be received, for example, from the search system 110 of FIG.1.

Query-relevant content is selected from a resource that is referenced bya search result that is included in the set of search results (604). Insome implementations, query-relevant content is selected for each searchresult in the set of search results. In other implementations, thequery-relevant content is selected for a threshold quantity (e.g., 3)search results that have been determined to be the most relevant searchresults (among the set of search results) for the search query. Forexample, the threshold quantity of search results can be the threesearch results that are associated with a highest relevance score forthe search query and/or that have been selected for presentation atdisplay positions that are the three most prominent display positions(e.g., the three search results selected for presentation at the firstthree positions on a search results page).

Query-relevant content includes text that matches at least one queryterm and/or other content that is associated with text that matches atleast one query term. For example, each of the terms “Belgian” and“waffle” each match a query term in the search query “Belgian waffle,”and are therefore query-relevant content for that search query.Additionally, an image (or other content) that is within a specifieddistance of query-relevant text is considered query-relevant content.Similarly, an image (or other content) having a filename (or othermetadata such as image labels) that match at least one query term arealso considered to be query-relevant content.

In some implementations, query-relevant content can be required toexactly match at least one query term in a search query. For example, inthese implementations, the term “Belgian” is considered to match thesearch query “Belgian waffle,” but will not match the search query“waffle from Belgium.” In other implementation, query-relevant contentfor a search query can include variations of a search term, such asstubs, plurals, present tenses, past tenses, future tenses, synonyms,and/or terms that have been determined to be similar to the search queryusing, for example, term clustering techniques, user feedback, and othermeasures of similarity (e.g., cosine similarity measures).

A context of the query-relevant content is analyzed (606). In someimplementations, analysis of the context of the query-relevant contentincludes an analysis of the location of the query-relevant content andan analysis of content that is presented within a threshold distance(e.g., a pre-specified quantity of pixels) of the query-relevantcontent. Analysis of the location of the query-relevant content canprovide information as to the relative importance of the query-relevantcontent within the resource. For example, text that is located in afootnote or a caption to an image may be considered less importantcontent than text that is in a body of a resource. Thus, query-relevantcontent that is located in a footnote or a caption may be consideredless relevant than query-relevant content that appears in an article oranother main body of text, as described in more detail below.

In addition to the location of the query-relevant content, othercharacteristics of the query-relevant content can be analyzed withrespect to the relative importance of the text. For example, text thatis linked to another network location (e.g., anchor text for a hypertextlink to another web page) may be considered less important and/or lessrelevant than text that is not linked to another network location. Thus,query-relevant content that links to another network location may beconsidered less relevant than query-relevant content that does not linkto another network location, as described in more detail below.

Analysis of the content that is presented within a threshold distance ofthe query-relevant content can provide additional information about therelative importance and/or relevance of the query-relevant content. Forexample, the term “waffle” is a query-relevant term for the search query“Belgian Waffle,” and may appear at several different locations of a webpage. However, some instances of the term “waffle” may be near otherterms that are more relevant to the search query than the terms that arenear other instances of the term “waffle.” For example, one instance ofthe term “waffle” may appear in the sentence “Waffles of the Belgianvariety originated in Belgium, and are leavened with yeast,” whileanother instance of “waffle” may appear in the sentence “Mother neverliked waffles or pancakes.” Analysis of these two sentences may resultin a determination that the first instance of the term “waffles” is morerelevant to the search query due to its proximity to the term “Belgian,”which is also a query term for the search query, whereas the term“waffle” in the second sentence is not located near instances of otherquery terms.

In some implementations, analysis of the context can include computing acontext score for the query-relevant content based on a quantity ofquery terms that are within a threshold number of pixels of thequery-relevant content and a total quantity of query terms that areincluded in the resource. For example, the resource can be analyzed todetermine a total quantity of query terms that are included in theresource, and locations of each of the query terms. The location of eachquery term and the location of the query-relevant content are then usedto determine a quantity of query terms that are within the distance ofthe query-relevant content. In turn, the context score is computed foreach instance of query-relevant content using the determined quantity ofquery terms and the total quantity of query terms. For example, a ratioof the determined quantity of query terms relative to the total quantityof query terms (or some function thereof) can be used as a context scorefor the query-relevant content.

The context score can also be adjusted based on a category to which thequery-relevant content belongs. For example, based on the analysis ofthe location of query-relevant content, the content can be categorizedas main content (i.e., content that appears in the body of a resource,article, and/or document) or supporting content (i.e., content that wasnot categorized as main content). The supporting content can includefootnotes, titles, captions, content that includes links to othernetwork resources, and other supporting content (e.g., tags that havebeen assigned to the page by users).

In some implementations, the context score for supporting content isreduced by a support reduction factor. For example, the supportreduction factor can be a value less than 1.0, and the context score forsupporting content is reduced by computing a product of the contextscore and the reduction factor. The support reduction factor can vary,for example, to represent relative levels of importance of differenttypes of supporting content. For example, a caption can have a highersupport factor than a footnote, which may have a higher support factorthan content that includes a link to another network location.

A set of query-relevant content is selected to be included in a pagepreview (608). In some implementations, the query-relevant content thatis selected is query-relevant content that satisfies a minimum relevancethreshold for the search query. The minimum relevance threshold can bespecified, for example, as a minimum context score for thequery-relevant content. For example, the set of query-relevant contentcan be the set of query-relevant content having the highest N contextscores, where the number N can depend on a size of the page preview slotin which the page preview will be presented, an initial zoom level forthe page preview, and/or a maximum number of page tears for the pagepreview.

A determination is made whether to insert a page tear in the pagepreview (610). In some implementations, the determination is made basedon whether the set of query-relevant content is visible in a pagepreview that does not include a page tear. The set of query-relevantcontent is visible in a page preview that does not include a page tearif a contiguous portion of the resource that includes the set ofquery-relevant content is fully presented in the page preview slot atthe initial zoom level for the page preview. For example, if the entireportion of the web page that includes the query-relevant content iswithin the borders of the page preview slot when presented at theinitial zoom level, a determination to not insert a page tear is made.

The set of query-relevant content is not visible in a page preview whenthe contiguous portion of the resource is not fully presented in thepage preview slot at the initial zoom level. For example, if any of thecontiguous portions of the resource is outside of the visible pagepreview when presented at the initial zoom level, a determination toinsert a page tear may be made.

In response to determining to not insert a page tear into the pagepreview, the set of query-relevant content is inserted into a pagepreview (612). The page preview can be, for example, a content templatein which content can be inserted. For example, the set of query-relevantcontent can be inserted into the page preview by inserting arepresentation (e.g., an image) of the contiguous portion of theresource in which the query-relevant content is presented. In someimplementations, the page preview is defined to have dimensions that areproportional to dimensions of the page preview slot in which the pagepreview will be presented. Additionally, the page preview can specify aninitial zoom level for the representation of the resource that isinserted into the page preview. Once the set of query-relevant contentis inserted into the page preview, data that cause presentation of thepage preview are provided (614), as described in more detail below.

In response to determining to insert a page tear in the page preview, apage tear is inserted in the page preview (616). In someimplementations, the page tear is inserted into the page preview byspecifying one or more locations at which a graphical element, such as aline, curve, pair of curves, or another visual indicator ofdiscontinuity is to be presented. The location of the page tear is usedto define at least two portions of the page preview in whichquery-relevant content can be presented.

Query-relevant content is inserted in each portion of the page preview(618). In some implementations, the query-relevant content that isinserted in each portion of the page preview is selected from adifferent portion of the resource than those portions of the resourcethat are represented in other portions of the page preview, as describedabove with reference to FIG. 3. The portion of the page preview in whichparticular query-relevant content is inserted can be selected, forexample, based on the relative position (relative location) of theparticular query-relevant content in the resource. For example,query-relevant content that appears higher in the resource than otherquery-relevant content can be presented at higher portions of the pagepreview than the other query-relevant content. Thus, the position of thequery-relevant content in the page preview can represent the relativelocation of the query-relevant content in the resource.

Data that cause presentation of the page preview are provided (614). Insome implementations, the data are provided to a search system thatprovides the data with data that cause presentation of the searchresults page. In other implementations, the data are provided to theclient device that submitted the search query.

The data that cause presentation of the page preview can include datathat cause presentation of a page preview that includes at least twoportions. The data that cause presentation of the two portions can alsoinclude data that cause presentation of query-relevant content in aportion of the page preview that represents the relative presentationposition of the query-relevant content in the resource.

In some implementations, the data that cause presentation of the pagepreview include data that cause presentation of the page preview in apage preview slot that is adjacent to the search result for which thepage preview was generated, e.g., HTML instructions. The data canfurther cause the page preview to be presented with an aspect ratio thatis substantially the same as the aspect ratio of the resource.

The data that cause presentation of the page preview can further includescripts or instructions that condition presentation of the page previewupon receipt of data indicative of a user action, as described withreference to FIG. 3. For example, the data can condition presentation ofthe page preview on receipt of data indicating that the user clicked ona page preview user interface element that is presented with the searchresults. The data can also condition presentation of the page preview onreceiving data specifying that the user clicked any portion of thedisplay in which the search result is presented. In someimplementations, user selection of the link to the resource referencedby the search result will not cause presentation of the page preview.

Additional actions upon which presentation of the page preview can beconditioned include actions such as a user placing a pointing deviceindicator over the search result (i.e., hovering over the searchresult). In some implementations, the page preview is presented onlyafter the search result is hovered over for more than a threshold periodof time. Prior to the threshold period of time, the search result can behighlighted in response to receiving data indicative of the hovering,where the highlighting is a visual indication that selection of thesearch result will initiate presentation of the page preview.

The data that cause presentation of the page preview can also includedata that cause query-relevant content to be presented at a higher zoomlevel than other content presented in a same portion of the pagepreview. For example, scripts or instructions can cause query-relevanttext to be presented at a larger font than other text that is presentedin a same portion of the page preview as the query-relevant text.

The data that cause presentation of the page preview can further includea link to the resource that is represented in the page preview. Forexample, an active link that upon user selection redirects the clientcomputer to the resource referenced by the search result can beassociated with the page preview.

In some implementations, more than one link can be included for aparticular page preview. When a page preview includes multiple portions(e.g., separated by a page tear), each of the portions of the pagepreview can be independently associated with a respective portion of thepage preview. For example, one link can be associated with a firstportion of the page preview and redirect the client device to a portionof the resource at which the query-relevant content of the first portionis presented. Similarly, another link can be associated with a secondportion of the page preview and redirect the client device to a portionof the resource at which the query-relevant content of the second pagepreview is presented.

FIG. 7 is another example process 700 for generating page previews. Theprocess 700 is a process by which search result data (i.e., data thatspecify a set of search results responsive to a search query) arereceived. A set of query-relevant content is selected to be included ina page preview. In turn, data is provided that cause presentation of apage preview in which at least a portion of the query relevant contentis presented at an initial zoom level and also presented at a higherzoom level (i.e., relative to the initial zoom level). In someimplementations, a determination is made that the resource includesadditional query relevant content that is not included in the pagepreview. In these implementations, data that cause presentation of theadditional query relevant content with the page preview can be provided.

The process 700 can be implemented, for example, by the previewapparatus 120 and/or the search system of FIG. 1. In someimplementations, the preview apparatus 120 is a data processingapparatus that includes one or more processors that are configured toperform actions of the process 700. In other implementations, a computerreadable medium can include instructions that when executed by acomputer cause the computer to perform actions of the process 700.

Data that specify a set of search results responsive to a search queryare received (702). In some implementations, the search query includesone or more query terms and the search results each represent a resourcethat has been determined to have at least a minimum threshold relevanceto at least one of the query terms. The data can include tidbits andsnippets that have been selected for presentation in the search result,and other tidbits and snippets that have not been selected forpresentation in the search result. The data that specify a set of searchresults can be received, for example, from the search system 110 of FIG.1.

A set of query-relevant content is selected to be included in a pagepreview (704). The query-relevant content can be selected in a mannersimilar to that described above with reference to FIG. 6. For example,the query-relevant content can be query-relevant text and/or queryrelevant images (or other query relevant content) that have beendetermined to match the search query (i.e., content that matches one ormore of the search terms).

Data that cause presentation of a page preview in which at least aportion of the query-relevant content is presented at both an initialzoom level and a higher zoom level are provided (706). In someimplementations, the initial zoom level is a zoom level at which boththe query-relevant content and other content are presented. For example,the initial zoom level can be a zoom level at which the content 510 a ispresented in FIG. 5. The higher zoom level is a zoom level is a zoomlevel that is higher than the initial zoom level, such that contentpresented at the higher zoom level appears larger than it appears at theinitial zoom level. For example, the higher zoom level can be a zoomlevel at which the content 510 b of FIG. 5 is presented. In thisexample, the data that cause presentation of the page preview includesdata that cause presentation of an instance of query-relevant content(i.e., text and/or images) at the initial zoom level (e.g., asrepresented by content 510 a) and also include data that causepresentation of an instance of the query-relevant content at a higherzoom level (e.g., as represented by content 510 b).

A portion of the page preview that is presented at the higher zoom levelcan include both query-relevant content and adjacent content. Forexample, the content 510 b includes the terms “Belgian Waffle” as wellas additional text that is adjacent to the terms “Belgian Waffle.” Insome implementations, query-relevant content (i.e., matching terms,matching images, and other matching content) that is presented at thehigher zoom level can be emphasized relative to other content that isalso presented at the higher zoom level. For example, in FIG. 5, thequery-relevant text “Belgian Waffle” has been bolded, while the othertext included in the content 510 b is not bolded. Other methods ofvisibly emphasizing content can also be used, such as highlighting thecontent, changing a font size of the content, and/or changing a fontcolor of the content.

In some implementations, the data that cause presentation of the pagepreview can include data that cause a portion of the page preview thatis presented at both the initial zoom level and the higher zoom level tobe visibly emphasized in the page preview. For example, the content 510a that is presented at the initial zoom level can be highlighted orotherwise visibly emphasized relative to content that is not presentedat the higher zoom level.

In some implementations, a determination is made that the resourceincludes additional query-relevant content that is not presented in thepage preview (708). The determination can be made, for example, bydetermining that additional content that matches the search query islocated at portions of the resource that have not been selected forpresentation in the page preview. As described above, a portion of asearch results page occupied by a page preview slot may be limited, suchthat all query-relevant content may not be presented in the pagepreview.

In response to determining that the resource includes the additionalquery-relevant content, data can be provided that cause presentation ofthe additional query-relevant content with the page preview (710). Forexample, data can be provided that cause presentation of the additionalquery-relevant content at a display position that is adjacent to thepage preview. Alternatively, the data can cause presentation of anoverlay in which the additional query-relevant content is presented at aportion of the display that overlaps with the page preview slot in whichthe page preview is presented. In some implementations, the data thatcause presentation of the additional query-relevant content can alsocause presentation of a user interface element indicating that theadditional query-relevant content represents a portion of the resourcethat is not presented in the page preview. For example, the page previewand/or the overlay in which the additional query-relevant content ispresented can include a directional arrow (or another indicator)indicating a direction of the non-visible portion of the resource fromwhich the additional query-relevant content was selected.

Embodiments of the subject matter and the operations described in thisspecification can be implemented in digital electronic circuitry, or incomputer software, firmware, or hardware, including the structuresdisclosed in this specification and their structural equivalents, or incombinations of one or more of them. Embodiments of the subject matterdescribed in this specification can be implemented as one or morecomputer programs, i.e., one or more modules of computer programinstructions, encoded on computer storage medium for execution by, or tocontrol the operation of, data processing apparatus. Alternatively or inaddition, the program instructions can be encoded on anartificially-generated propagated signal, e.g., a machine-generatedelectrical, optical, or electromagnetic signal, that is generated toencode information for transmission to suitable receiver apparatus forexecution by a data processing apparatus. A computer storage medium canbe, or be included in, a computer-readable storage device, acomputer-readable storage substrate, a random or serial access memoryarray or device, or a combination of one or more of them. Moreover,while a computer storage medium is not a propagated signal, a computerstorage medium can be a source or destination of computer programinstructions encoded in an artificially-generated propagated signal. Thecomputer storage medium can also be, or be included in, one or moreseparate physical components or media (e.g., multiple CDs, disks, orother storage devices).

The operations described in this specification can be implemented asoperations performed by a data processing apparatus on data stored onone or more computer-readable storage devices or received from othersources.

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, a system on a chip, or multipleones, or combinations, of the foregoing The apparatus can includespecial purpose logic circuitry, e.g., an FPGA (field programmable gatearray) or an ASIC (application-specific integrated circuit). Theapparatus can also include, in addition to hardware, code that createsan execution environment for the computer program in question, e.g.,code that constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, a cross-platform runtimeenvironment, a virtual machine, or a combination of one or more of them.The apparatus and execution environment can realize various differentcomputing model infrastructures, such as web services, distributedcomputing and grid computing infrastructures.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, declarative orprocedural languages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, object, orother unit suitable for use in a computing environment. A computerprogram may, but need not, correspond to a file in a file system. Aprogram can be stored in a portion of a file that holds other programsor data (e.g., one or more scripts stored in a markup languagedocument), in a single file dedicated to the program in question, or inmultiple coordinated files (e.g., files that store one or more modules,sub-programs, or portions of code). A computer program can be deployedto be executed on one computer or on multiple computers that are locatedat one site or distributed across multiple sites and interconnected by acommunication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform actions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. The essential elements of a computer area processor for performing actions in accordance with instructions andone or more memory devices for storing instructions and data. Generally,a computer will also include, or be operatively coupled to receive datafrom or transfer data to, or both, one or more mass storage devices forstoring data, e.g., magnetic, magneto-optical disks, or optical disks.However, a computer need not have such devices. Moreover, a computer canbe embedded in another device, e.g., a mobile telephone, a personaldigital assistant (PDA), a mobile audio or video player, a game console,a Global Positioning System (GPS) receiver, or a portable storage device(e.g., a universal serial bus (USB) flash drive), to name just a few.Devices suitable for storing computer program instructions and datainclude all forms of non-volatile memory, media and memory devices,including by way of example semiconductor memory devices, e.g., EPROM,EEPROM, and flash memory devices; magnetic disks, e.g., internal harddisks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROMdisks. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subjectmatter described in this specification can be implemented on a computerhaving a display device, e.g., a CRT (cathode ray tube) or LCD (liquidcrystal display) monitor, for displaying information to the user and akeyboard and a pointing device, e.g., a mouse or a trackball, by whichthe user can provide input to the computer. Other kinds of devices canbe used to provide for interaction with a user as well; for example,feedback provided to the user can be any form of sensory feedback, e.g.,visual feedback, auditory feedback, or tactile feedback; and input fromthe user can be received in any form, including acoustic, speech, ortactile input. In addition, a computer can interact with a user bysending documents to and receiving documents from a device that is usedby the user; for example, by sending web pages to a web browser on auser's client device in response to requests received from the webbrowser.

Embodiments of the subject matter described in this specification can beimplemented in a computing system that includes a back-end component,e.g., as a data server, or that includes a middleware component, e.g.,an application server, or that includes a front-end component, e.g., aclient computer having a graphical user interface or a Web browserthrough which a user can interact with an implementation of the subjectmatter described in this specification, or any combination of one ormore such back-end, middleware, or front-end components. The componentsof the system can be interconnected by any form or medium of digitaldata communication, e.g., a communication network. Examples ofcommunication networks include a local area network (“LAN”) and a widearea network (“WAN”), an inter-network (e.g., the Internet), andpeer-to-peer networks (e.g., ad hoc peer-to-peer networks).

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other. In someembodiments, a server transmits data (e.g., an HTML page) to a clientdevice (e.g., for purposes of displaying data to and receiving userinput from a user interacting with the client device). Data generated atthe client device (e.g., a result of the user interaction) can bereceived from the client device at the server.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

What is claimed is:
 1. A method performed by data processing apparatus,the method comprising: receiving data that specify a set of searchresults responsive to a search query, the search query including one ormore query terms; for one search result in the set of search results:identifying, as portions of query-relevant content in a resourcereferenced by the search result, text that matches at least one queryterm of the search query; for each of two or more portions of theidentified query-relevant content: computing a first score for theportion of query-relevant content, the first score being computed basedon both a quantity of query terms that are within a threshold number ofpixels of the portion of query-relevant content and a total quantity ofquery terms that are included in the resource; determining a contentcategory for the portion of query-relevant content; and adjusting thefirst score based on the content category for the portion ofquery-relevant content; selecting a set of query-relevant content basedon the adjusted first scores of the two or more portions ofquery-relevant content; inserting a page tear into a page preview inwhich the two or more portions of query-relevant content will bepresented, the page tear defining a first portion and a second portionof the page preview, the first portion being different from the secondportion; inserting a first portion of query-relevant content from theresource into the first portion of the page preview; inserting a secondportion of query-relevant content from the resource into the secondportion of the page preview, the second portion of query-relevantcontent being content selected from a portion of the resource that isnot presented in the first portion of query-relevant content; andproviding data that cause presentation of the page preview.
 2. Themethod of claim 1, further comprising: analyzing a context of theportion of query-relevant content, the context including a location ofthe portion of query-relevant content and other content that appearswithin a threshold distance from the portion of query-relevant content;wherein selecting the set of query-relevant content comprises selecting,based on the context, the two or more portions of query-relevant contentthat satisfy a minimum relevance threshold.
 3. The method of claim 1,wherein adjusting the first score comprises reducing the first score inresponse to determining that the content category is one of a footnoteor anchor text that links to another resource.
 4. The method of claim 1,wherein providing data that cause presentation of the page previewcomprises providing data that cause presentation of the first portion ofthe page preview and the second portion of the page preview atpresentation positions that represent relative locations of the firstportion of query-relevant content and the second portion ofquery-relevant content in the resource.
 5. The method of claim 1,wherein providing data that cause presentation of the page previewcomprises providing data that causes presentation of the page preview ata page preview slot that is adjacent to the search query.
 6. The methodof claim 1, wherein providing data that cause presentation of the pagepreview comprises providing data that cause presentation of the pagepreview in response to user selection of a page preview user interfaceelement that is presented with the search results.
 7. The method ofclaim 1, wherein providing data that cause presentation of the pagepreview comprises providing data that includes a link to the resourcereferenced by the search result.
 8. The method of claim 7, whereinproviding data that includes a link to the resource comprises providingdata that includes a first link to a location of the resource at whichthe first portion of query-relevant content is located and furtherincludes a second link to a location of the resource at which the secondportion of query-relevant content is located.
 9. The method of claim 8,wherein the first link is associated with the first portion of the pagepreview and the second link is associated with the second portion of thepage preview.
 10. The method of claim 1, wherein providing data thatcause presentation of the page preview comprises providing data thatcause presentation of the page preview in response to user selection ofany portion of the search result other than a link to the resourcereferenced by the search result.
 11. The method of claim 10, whereinproviding data that cause presentation of the page preview furthercomprises providing data that cause the search result to be highlightedin response to receiving data indicating that a pointing deviceindicator is located over the search result.
 12. The method of claim 1,wherein providing data that cause presentation of the page previewcomprises providing data that cause the first query-relevant content tobe presented with a larger font than at least a portion of other contentincluded in the first portion of the page preview.
 13. A computerstorage medium encoded with a computer program, the program comprisinginstructions that when executed by data processing apparatus cause thedata processing apparatus to perform operations comprising: receivingdata that specify a set of search results responsive to a search query,the search query including one or more query terms; and for one searchresult in the set of search results: identifying, as portions ofquery-relevant content in a resource referenced by the search result,text that matches at least one query term of the search query; for eachof two or more portions of the identified query-relevant content:computing a first score for the portion of query-relevant content, thefirst score being computed based on both a quantity of query terms thatare within a threshold number of pixels of the portion of query-relevantcontent and a total quantity of query terms that are included in theresource; determining a content category for the portion ofquery-relevant content; and adjusting the first score based on thecontent category for the portion of query-relevant content; selecting aset of query-relevant content based on the adjusted first scores of thetwo or more portions of query-relevant content; inserting a page tearinto a page preview in which the two or more portions of query-relevantcontent will be presented, the page tear defining a first portion and asecond portion of the page preview, the first portion being differentfrom the second portion; inserting a first portion of query-relevantcontent from the resource into the first portion of the page preview;inserting a second portion of query-relevant content from the resourceinto the second portion of the page preview, the second portion ofquery-relevant content being content selected from a portion of theresource that is not presented in the first portion of query-relevantcontent; and providing data that cause presentation of the page preview.14. A system comprising: a client device; and one or more computersoperable to interact with the device and further operable to: receivedata that specify a set of search results responsive to a search query,the search query including one or more query terms; and for one searchresult in the set of search results: identify, as portions ofquery-relevant content in a resource referenced by the search result,text that matches at least one query term of the search query; for eachof two or more portions of the identified query-relevant content:compute a first score for the portion of query-relevant content, thefirst score being computed based on both a quantity of query terms thatare within a threshold number of pixels of the portion of query-relevantcontent and a total quantity of query terms that are included in theresource; determine a content category for the portion of query-relevantcontent; and adjust the first score based on the content category forthe portion of query-relevant content; select a set of query-relevantcontent based on the adjusted first scores of the two or more portionsof query-relevant content; insert a page tear into a page preview inwhich the two or more portions of query-relevant content will bepresented, the page tear defining a first portion and a second portionof the page preview, the first portion being different from the secondportion; insert a first portion of query-relevant content from theresource into the first portion of the page preview; insert a secondportion of query-relevant content from the resource into the secondportion of the page preview, the second portion of query-relevantcontent being content selected from a portion of the resource that isnot presented in the first portion of query-relevant content; andprovide data that cause presentation of the page preview.
 15. The systemof claim 14, wherein the one or more computers comprise a serveroperable to interact with the device through a data communicationnetwork, and the device is operable to interact with the server as aclient.
 16. The system of claim 14, wherein the one or more computersare further operable to: analyze a context of the portion ofquery-relevant content, the context including a location of the portionof query-relevant content and text that appears within a thresholddistance from the portion of query-relevant content; and select, basedon the context, the portions of query-relevant content that satisfy aminimum relevance threshold for inclusion in the set of query-relevantcontent.
 17. The system of claim 14, wherein the one or more computersare further operable to provide data that cause presentation of the pagepreview, the data further comprising a first hypertext link to alocation of the resource at which the first portion of query-relevantcontent is located and further includes a second hypertext link to alocation of the resource at which the second portion of query-relevantcontent is located.
 18. A method performed by data processing apparatus,the method comprising: receiving data that specify a set of searchresults responsive to a search query, the search query including one ormore query terms; and for one search result in the set of searchresults: identifying, as portions of query-relevant content in aresource referenced by the search result, text that matches at least onequery term of the search query; for each of two or more portions of theidentified query-relevant content: computing a first score for theportion of query-relevant content, the first score being computed basedon both a quantity of query terms that are within a threshold number ofpixels of the portion of query-relevant content and a total quantity ofquery terms that are included in the resource; determining a contentcategory for the portion of query-relevant content; and adjusting thefirst score based on the content category for the portion ofquery-relevant content; selecting a set of query-relevant content basedon the adjusted first scores of the two or more portions ofquery-relevant content; inserting a page tear into a page preview inwhich the two or more portions of query-relevant content will bepresented, the page tear defining a first portion and a second portionof the page preview, the first portion being different from the secondportion; inserting a first portion of query-relevant content from theresource into the first portion of the page preview; inserting a secondportion of query-relevant content from the resource into the secondportion of the page preview, the second portion of query-relevantcontent being content selected from a portion of the resource that isnot presented in the first portion of query-relevant content; andproviding data that cause presentation of the page preview, the datacomprising data that cause presentation of the query-relevant content atan initial zoom level and at a higher zoom level, the initial zoom levelbeing a zoom level at which both the query-relevant content and othercontent from the resource are presented in the page preview, the higherzoom level being a zoom level that is higher than the initial zoomlevel.
 19. The method of claim 18, wherein: providing data that causepresentation of the page preview comprises: providing data that causepresentation of an instance of the query-relevant content at the initialzoom level; and providing data that cause presentation of anotherinstance of the query-relevant content at the higher zoom level.
 20. Themethod of claim 19, wherein the query-relevant content is presented atthe higher zoom level and visibly emphasized relative to other contentpresented in the page preview.
 21. The method of claim 18, whereinselecting a set of query-relevant content comprises selecting at leastone query-relevant image; and providing data that cause presentation ofthe page preview comprises: providing data that cause presentation of aninstance of the query-relevant image at the initial zoom level; andproviding data that cause presentation of another instance of thequery-relevant image at the higher zoom level.
 22. The method of claim18, wherein providing data that cause presentation of the page previewfurther comprises providing data that cause a portion of the pagepreview that is presented at both the initial zoom level and the higherzoom level to be visibly emphasized at the initial zoom level.
 23. Themethod of claim 18, further comprising: determining that the resourceincludes additional query-relevant content that is not presented in thepage preview; and providing data that cause presentation of theadditional query-relevant content with the page preview, thepresentation of the additional query-relevant content including a userinterface element indicating that the additional query-relevant contentis located at a portion of the resource that is not presented in theinitial page preview.
 24. A system comprising: a client device; and oneor more computers operable to interact with the device and furtheroperable to: receive data that specify a set of search resultsresponsive to a search query, the search query including one or morequery terms; and for one search result in the set of search results:identify, as portions of query-relevant content in a resource referencedby the search result, text that matches at least one query term of thesearch query; for each of two or more portions of the identifiedquery-relevant content: compute a first score for the portion ofquery-relevant content, the first score being computed based on both aquantity of query terms that are within a threshold number of pixels ofthe portion of query-relevant content and a total quantity of queryterms that are included in the resource; determine a content categoryfor the portion of query-relevant content; and adjust the first scorebased on the content category for the portion of query-relevant content;select a set of query-relevant content based on the adjusted firstscores of the two or more portions of query-relevant content; insert apage tear into a page preview in which the two or more portions ofquery-relevant content will be presented, the page tear defining a firstportion and a second portion of the page preview, the first portionbeing different from the second portion; insert a first portion ofquery-relevant content from the resource into the first portion of thepage preview; insert a second portion of query-relevant content from theresource into the second portion of the page preview, the second portionof query-relevant content being content selected from a portion of theresource that is not presented in the first portion of query-relevantcontent; and provide data that cause presentation of the page preview,the data comprising data that cause presentation of the query-relevantcontent at an initial zoom level and at a higher zoom level, the initialzoom level being a zoom level at which both the query-relevant contentand other content from the resource are presented in the page preview,the higher zoom level being a zoom level that is higher than the initialzoom level.
 25. A computer storage medium encoded with a computerprogram, the program comprising instructions that when executed by dataprocessing apparatus cause the data processing apparatus to performoperations comprising: receiving data that specify a set of searchresults responsive to a search query, the search query including one ormore query terms; and for one search result in the set of searchresults: identifying, as portions of query-relevant content in aresource referenced by the search result, text that matches at least onequery term of the search query; for each of two or more portions of theidentified query-relevant content: computing a first score for theportion of query-relevant content, the first score being computed basedon both a quantity of query terms that are within a threshold number ofpixels of the portion of query-relevant content and a total quantity ofquery terms that are included in the resource; determining a contentcategory for the portion of query-relevant content; and adjusting thefirst score based on the content category for the portion ofquery-relevant content; selecting a set of query-relevant content basedon the adjusted first scores of the two or more portions ofquery-relevant content; inserting a page tear into a page preview inwhich the two or more portions of query-relevant content will bepresented, the page tear defining a first portion and a second portionof the page preview, the first portion being different from the secondportion; inserting a first portion of query-relevant content from theresource into the first portion of the page preview; inserting a secondportion of query-relevant content from the resource into the secondportion of the page preview, the second portion of query-relevantcontent being content selected from a portion of the resource that isnot presented in the first portion of query-relevant content; andproviding data that cause presentation of the page preview, the datacomprising data that cause presentation of the query-relevant content atan initial zoom level and at a higher zoom level, the initial zoom levelbeing a zoom level at which both the query-relevant content and othercontent from the resource are presented in the page preview, the higherzoom level being a zoom level that is higher than the initial zoomlevel.